Biological studies on Encarsia porteri (Mercet) (Hymenoptera: Aphelinidae) an heterotrophic parasitoid of the Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) complex

Encarsia porteri is an heterotrophic species. Female progeny develop as primary parasitoids of whiteflies, whereas male progeny occur as primary parasitoids of lepidopteran eggs. This parasitoid was found parasitizing the local biotype of Bemisia tabaci (ARG1) on cotton, soybean and alfalfa in Argentina. The main biological parameters of E porteri were recorded under laboratory conditions. Preimaginal developmental time of females on whitefly nymphs was significantly faster (P < 0.05) on tomato (19.20 +/- 0.28 days) than on cotton (23.40 +/- 0.21 days). The longevity of adult female did not differ between host plant species (P > 0.05) (tomato: 18.85 +/- 2.49 days, cotton: 20.52 +/- 0.94 days) at 21.4 +/- 0.4 degreesC. Developmental time and longevity for E. porteri males were estimated on five lepidopteran host species (Antiearsia gemmatalis, Cydia pomonella, Diatraea saccharalis, Crocidosema aporema, and Sitotroga cerealella). Males developed more quickly on A. gemmatalis than they did on D. saccharalis and C pomonella eggs, whereas no differences were observed with C aporema and S. cerealella (P < 0.05). For the longevity no differences were observed between host species (P > 0.05). Preference of E porteri females for some lepidopteran eggs (A. gemmatalis, C pomonella, D. saccharalis, and S. cerealella) was also studied. The eggs of the noctuid A. gemmatalis were preferred by E porteri females for allocating their male progeny (P < 0.05). These results suggest that A. gemmatalis is the most suitable host for E porteri males among the species tested. (C) 2003 Elsevier Inc. All rights reserved.